Have I got this wrong or am I right in recalling Marco's amp has 2x KT88 per channel ?[/QUOTE]
yes, two KT88's in push pull run in AB will give 100 watts.
in marcos amp they are run in the warm side of AB1.
anthony...
Audio Engineer; Moderator
Location: South Wales
Posts: 9,148
I'm NotTakingLifeTooSeriouslyTheseDays.
Have I got this wrong or am I right in recalling Marco's amp has 2x KT88 per channel ?[/QUOTE]
yes, two KT88's in push pull run in AB will give 100 watts.
in marcos amp they are run in the warm side of AB1.
anthony...
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Location: Wrexham, North Wales, UK
Posts: 111,027
I'm AudioAl'sArbiterForPISHANTO.
More unsubstantiated waffle. Is that like the way you wouldn't guarantee how long the transport mech in my Sony will last? It'll outlast you, that's for sure!Originally Posted by jcbrum
Marco.
Main System
Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & regulator mods]. Funk Firm APM Achromat with Nagaoka GL-601 Crystal Record Weight. Isonoe feet & boots. Ortofon RS-212D tonearm with Denon DL-103GL in a Denon PCL-300 headshell, fitted with Funk Firm Houdini and Kondo SL-115 pure-silver cartridge leads.
Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp and Denon AU-310 SUT.
Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.
CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.
Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.
Preamps: Heavily-modified Croft Charisma-X. Power Amps: Tube Distinctions Copper Amp, fitted with Tungsol KT-150s. Quad 306.
Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.
Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.
Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.
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Posts: 424
Well done,Erm... Yes.so did I
Audio Engineer; Moderator
Location: South Wales
Posts: 9,148
I'm NotTakingLifeTooSeriouslyTheseDays.
example,I have some early transformer coupled amps in my collection.I bought them new in 1967 I think.
So Marco's amp is only flat at 30w, that's what I expected. I wouldn't like to guarantee how long it would deliver 60w on a warm day !
Have I got this wrong or am I right in recalling Marco's amp has 2x KT88 per channel ?
kt88's were used in for example, loss testers in the steel industry, they drove huge triode valves flat out for months at a time!
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Posts: 424
100w is a "catalogue" figure, at that level the distortion would be awful and they would go bang v quickly. Don't you agree ?
Audio Engineer; Moderator
Location: South Wales
Posts: 9,148
I'm NotTakingLifeTooSeriouslyTheseDays.
no,[/B]
100w is a "catalogue" figure, at that level the distortion would be awful and they would go bang v quickly. Don't you agree ?
i dont agree, the distortion figures are relatively high [10%] at that power without feedback, but the 100 watt power output is feasible, and definitely achievable, and with sufficient cooling, sustainable!
Last edited by anthonyTD; 03-05-2008 at 22:52.
Audio Engineer; Moderator
Location: South Wales
Posts: 9,148
I'm NotTakingLifeTooSeriouslyTheseDays.
off to bed now folks...
anthony...
Site Owner/Administrator
Location: Wrexham, North Wales, UK
Posts: 111,027
I'm AudioAl'sArbiterForPISHANTO.
Ok, matey. You've well and truly kicked JC's ass now anyway! Nighty night
Marco.
Main System
Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & regulator mods]. Funk Firm APM Achromat with Nagaoka GL-601 Crystal Record Weight. Isonoe feet & boots. Ortofon RS-212D tonearm with Denon DL-103GL in a Denon PCL-300 headshell, fitted with Funk Firm Houdini and Kondo SL-115 pure-silver cartridge leads.
Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp and Denon AU-310 SUT.
Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.
CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.
Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.
Preamps: Heavily-modified Croft Charisma-X. Power Amps: Tube Distinctions Copper Amp, fitted with Tungsol KT-150s. Quad 306.
Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.
Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.
Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.
Banned
Posts: 424
The limiting factor with most valves is the anode dissipation of heat, which is mainly controlled by the bias setting, not the output power.
In class A, KT88's might provide 10w out, in AB 30w, in class C 60w, in class D 100w.
It is therefore misleading to talk in terms of output power and anyway 60w is only 3db louder than 30w (v small difference)
To exceed double the volume (spl) you'd probably need to go from 30w to 300w.
In an attempt to do that in a push pull design the crossover distortion would be enormous >10% and clipping would be absolutely inevitable, but some do regard this as "involving musicality" and even get to like the sound.
Marco has already set fire to his amplifier once
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Location: North East UK
Posts: 6,358
I'm InSpace.
More like 900W
Shian7
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